Pushbutton can closure



March 26, 1968 T. R. KELLEY 3,374,921

PUSHBUTTON CAN CLOSURE Filed Aug. 16, 1966 B I I 2 23 )30 22\ ZOE-\- B ,2 INVENTOR g 4 Theron R. Kelley ATTORNEYS United States Patent 3,374,921 PUSHBUTTON CAN CLOSURE Theron R. Kelley, Mattapoisett, Mass., assignor to Tedan, Inc., West Hanover, Mass., a corporation of Massachusetts Filed Aug. 16, 1966, Ser. No. 572,831 4 Claims. (Cl. 220-60) The invention disclosed herein is a removable-replaceable closure for the opening of a container.

It is recognized that the art in this field is extensive. So far as applicant is aware, neither the patented nor practical art has produced a successful internal pressure-resistant removable-replaceable closure for an opening in a plate having parallel upper and lower surfaces and of predetermined thickness such as a can top, without the opening having special peripheral configuration, such as rolled flanges, beading or the like.

The object of the invention is to provide such a closure, the closure being formed of a deformable and elastomer material, preferably polyurethane, having a plug portion entirely receivable in the container, a plate engaging sealing groove, a top restraining flange, a pull tab, and a pushbutton, all molded or otherwise produced as a unit structure.

Basically, the closure differs from those known, in that the sealing groove must be expanded to seat and then contracts to engage the plate and exerts compression forces holding it in position. Additionally, the plug portion is entirely within the container below the groove portion and may only be forced out from inside the container by a pressure suflicient to extrude it through the plate opening.

Because of the above, the surface engagement with the lower or inner surface of the plate is relatively small whereby removal and replacement is readily accomplished.

The foregoing and other objects and advantages will become apparent from the description of the closure, when read in light of the drawings wherein:

FIGURE 1 is a top view of the closure;

FIGURE 2 is a reverse side of FIGURE 1;

FIGURE 3 is a sectional view on line 3-3 of FIG- URE 1 and showing the closure resting in a plate opening prior to scaling;

FIGURE 4 is an exaggerated view similar to FIG- URE 3, with the closure separated into parts to better illustrate the invention;

FIGURE 5 is a perspective view of a container with a flat top and symmetrical opening therein;

FIGURE 6 is a view on line 6-6 of FIGURE 5; and

FIGURE 7 is a sectional view showing the closure in closing position in the can top.

More particularly, the closure comprises a plug portion 12, a circumferential collar 18, a circumferential sealing groove 21 in the collar 18, a circumferential flange extending radially outward from collar 18, a pull tab 25, extending outwardly radially from flange 20, and a pushbutton 30 positioned centrally of the plug portion 12. The closure is used to seal the opening 42 in the plate top 46 of the container 40.

The plug portion 12 is substantially the segment of a sphere having a top face 14, a parallel bottom face 16 and a side wall curving inwardly from the top to the bottom face. The circumferential collar 18 extends upwardly from the periphery of the top face 14 of plug 12 and is substantially rectangular in cross-section. The outwardly opening circumferential sealing groove 21 is also substantially rectangular in cross-section and is entirely in the collar 18 and lies in a plane parallel to but positioned above the top face 14 of plug 12 whereby when the closure is in position the plug lies wholly within the container. The groove 21 has parallel lower and upper flat faces 24 and 26 and a vertical inner end wall 22. The diameter of the closure "ice at the top of the collar wall portion 19, between the sealing groove and plug, which diameter is also that of the bottom face of groove 21, is larger than the diameter of the plate opening in which the closure is to be positioned. The inner diameter of the groove, that is of the wall 22, is also longer than the diameter of the plate opening. Additionally, the vertical spacing between the top and bottom faces of the groove, which shall be called the groove thickness is less than the thickness of the plate 46. With the groove so positioned, the collar 18 is divided into an upper and lower part connected by the narrow throat 23, which has the same vertical thickness as the groove and constitutes a flexing hinge whereby the upper portion of the collar may be flexed upwardly.

'Coextensive with and extending radially outward from the collar is the circumferential restraining flange 20, its lower surface lying in the same plane as the upper face 26 of the groove 21 and its upper face in the same plane as the upper face of shoulder 18. The lower face will engage the top plate of the container and overlie it for a distance beyond the plate opening. A pull tab 21 extends radially outward from the flange 20 at one point thereon.

Positioned centrally of the top face 14 of the plug 12 is a generally cylindrical pushbutton 30, having a lesser diameter than the inner diameter of the collar 18 and defining therewith a cylindrical trough 31. The bottom of the trough is the portion of plug 12 underlying it, and this underlying portion of the plug constitutes a web connecting portion of high stretch and deformability between the portion underlying pushbutton 30 and collar 18.

With the above construction, if an axial force is placed on pushbutton 30 as indicated by the arrow in FIGURE 3, wherein the closure is resting on the periphery of the plate opening, the closure will be axially elongated as indicated by the dotted lines, the outer diametersof the plug and collar through wall portion 19 being shortened and the plug and collar wall portion 19 beneath the groove will pass through the opening until the flange 20 engages the top face of the plate, the flange being of suflicient width to prevent its being pushed through the opening.

As previously indicated, the closure is intended for closing a symmetrical opening 42, shown as circular, in the top of a container 40. The top is a plate 41 having top and bottom parallel faces 46 and 48 and a predetermined thickness (usually can stock runs .010 to .012 inch in thickness). The opening 42 is punched or otherwise cut out by any means which provide a relatively smooth peripheral surface. The containers are usually made with a top rim 44, and the closure is made so that the top surfaces of the shoulder, flange, and pushbutton do not lie above the top edge of the rim. This construction permits stacking of the containers which is an important feature from an economical viewpoint, as it reduces shipping and storage space.

With the closure seated in sealing position, as shown in FIGURE 7, a squeeze fit results, the material at the groove diameter is under compression and is exerting an outward force against the edge of the plate opening as indicated by the arrows A, and the material having been stretched to increase the groove thickness, is producing compression forces on the upper and lower surfaces of the plate as indicated by the arrows B. The pressure on the top surface will be greatest at the sealing groove, but will extend outwardly along the flange, thus increasing the holding power over that which atmospheric pressure alone will produce.

To remove the closure the tab 25 is raised and pulled diametrically across the closure as indicated in FIGURE 7, the tab will hinge about the throat 23- and draw the lower surface of the groove beyond the periphery of the plate opening. The opening can be assisted by simultaneously exerting pressure on pushbutton 30'.

3 As the drawings have been exaggerated to better illustrate the invention, the following dimensions are given for a closure of a /41" diameter opening, the material used being urethane with a durometer reading of 75A on the Shore scale:

. Inches Diameter of plate opening or Inside diameter of groove Thickness of plate .010 Thickness of groove .005 Vertical spacing between groove and top face of plug Thickness of plug between faces Under tests for a period approximating six months, a closure of the above type remained in sealing position under the following conditions:

(1) Ten pounds internal pressure, closure bulged outwardly (as did top of container), but closure held pressure and after five months lost one and one-half pounds.

(2) Twenty-four inches vacuum, closure bulged inwardly but did not loose seal, container acts as barometer and vacuum varies i from 24.

(3) Container contents frozen without an air space, closure bulged but did not loose seal.

(4) Container contents frozen with /8" airspaceclosure was not affected.

Closures of elastomeric material in durometer scales of from 70A to 90A are satisfactory depending upon the packaged contents and internal pressure expected, for higher pressure the higher range is used.

Although the closure has been defined with respect to a circular opening, it may be used with openings which are symmetrical to each side of a single chord, such as an oval or ovoid, closures of this type are more expensive to produce, and the preferred embodiment is the one shown and described.

The following is claimed:

1. A removable-replaceable elastomer closure for a symmetrical opening in a plate of predetermined thickness, including (a) a plug portion substantially the segment of a sphere having top and bottom faces, the outer circumferential wall of the plug curving downwardly and inwardly from the top to the bottom face,

(b) a circumferential collar of substantially rectangular cross-section area extending'upwardly from the top face of the plug portion, the outer diameter of the collar being longer than the plate opening diameter,

(c) a circumferential, substantially rectangular groove with-its open end facing outwardly provided in the collar,

(d) the groove being in a plane parallel ,to and spaced above the top face of the plug,

(e) the inner diameter of the groove being longer than the diameter of the plate opening, and the thickness of the groove being less than the thickness of the plate,

(f) a flange extending radially outward from the collar above the groove, the lower face of the flange lying in the same plane as the upper face of the groove,

(g) a pull tab extending radially outward from the flange,

(h) a pushbutton extending upwardly from the plug and positioned substantially centrally of the plug, the outer wall of the pushbutton and inner wall of the collar defining a trough therebetween,

(i) whereby the plug material below the trough constitutes a readily flexible web transmitting pressure exerted on the pushbutton axially of the closure to elongate it and reduce its circumference to pass through the plate opening.

2. The closure in claim 1 wherein the inner diameter of the groove is longer than the diameter of the plate opening and the groove thickness is not more than of the plate thickness.

3. The closure in claim 2 wherein the above the top face of the plug.

4. The closure in claim 1 wherein the closure is urethane in the durometer range between and A on the Shore scale.

groove is spaced References Cited UNITED STATES PATENTS 3/1963 Corrinet 220--60 12/1964 Duggan 22060 

1. A REMOVABLE-REPLACEABLE ELASTOMER CLOSURE FOR A SYMMETRICAL OPENING IN A PLATE OF PREDETERMINED THICKNESS, INCLUDING (A) A PLUG PORTION SUBSTANTIALLY THE SEGMENT OF A SPHERE HAVING TOP AND BOTTOM FACES, THE OUTER CIRCUMFERENTIAL WALL OF THE PLUG CURVING DOWNWARDLY AND INWARDLY FROM THE TOP TO THE BOTTOM FACE, (B) A CIRCUMFERENTIAL COLLAR OF SUBSTANTIALLY RECTANGULAR CROSS-SECTION AREA EXTENDING UPWARDLY FROM THE TOP FACE OF THE PLUG PORTION, THE OUTER DIAMETER OF THE COLLAR BEING LONGER THAN THE PLATE OPENING DIAMETER, (C) A CIRCUMFERENTIAL, SUBSTANTIALLY RECTANGULAR GROOVE WITH ITS OPEN END FACING OUTWARDLY PROVIDED IN THE COLLAR, (D) THE GROOVE BEING IN A PLANE PARALLEL TO AND SPACED ABOVE THE TOP FACE OF THE PLUG, (E) THE INNER DIAMETER OF THE GROOVE BEING LONGER THAN THE DIAMETER OF THE PLATE OPENING, AND THE THICKNESS OF THE GROOVE BEING LESS THAN THE THICKNESS OF THE PLATE, (F) A FLANGE EXTENDING DOWNWARDLY OUTWARD FROM THE COLLAR ABOVE THE GROOVE, THE LOWER FACE OF THE FLANGE LYING IN THE SAME PLANE AS THE UPPER FACE OF THE GROOVE, (G) A PULL OF EXTENDING RADIALLY OUTWARD FROM THE FLANGE, (H) A PUSHBUTTON EXTENDING UPWARDLY FROM THE PLUG AND POSITIONED SUBSTANTIALLY CENTRALLY OF THE PLUG, THE OUTER WALL OF THE PUSHBUTTON AND INNER WALL OF THE COLLAR DEFINING A TROUGH THEREBETWEEN, (I) WHEREBY THE PLUG MATERIAL BELOW THE TROUGH CONSTITUTES A READILY FLEXIBLE WEB TRANSMITTING PRESSURE EXERTED ON THE PUSHBUTTON AXIALLY OF THE CLOSURE TO ELONGATE IT AND REDUCE ITS CIRCUMFERENCE TO PASS THROUGH THE PLATE OPENING. 